Long-term Results of Developmental Hip Dysplasia Under Therapy With Pavlik Harness.

INTRODUCTION: The Pavlik harness is a commonly used treatment for developmental dysplasia of the hip (DDH) of types IIc or worse, based on the Graf classification. This study aimed to assess the long-term follow-up outcomes after treating DDH with the Pavlik harness. METHODS: Between 1995 and 2006, ultrasound screening was conducted on 7372 newborns within the first days of life. Among them, 203 dysplastic hips in 152 patients, whose sonograms were Graf type IIc or worse, were treated with Pavlik harness. Treatment was discontinued if the measurement indicated Graf type Ia/b. More than 20 years later (mean: 20.46 y), patients were invited for clinical evaluation (Oxford Hips Score, Schulthess Hip Score, Harris Hip Score) and radiologic examination (center-edge angle according to Wiberg and the Severis classification, the rate of roofing of the femoral head via the Reimers migration percentage, and the Sharp angle). RESULTS: Of the 152 patients, 60 (39.5%) participants with 80 (39.4%) affected hips (57.7% type IIc, 7.9% type D, and 15.6% type IIIa/b) were reexamined. The average follow-up duration was 20.5 years, with a maximum of 25.9 years. According to the Severin's classification, only 2 (3.77%) patients, each with one affected hip, showed slight residual dysplasia. The Reimer's migration percentage indicated an average of almost 90% canopy cover in the patient collective studied. No avascular necrosis was found, and the Sharp angle showed an average of almost 38 degrees. Only 4 participants with each one affected hip showed residual dysplasia according to the Sharp angle. The clinical results were quite satisfying, as none of the patients experienced hip pain that significantly limited their everyday activities or sports engagement, requiring medical attention before this study.Conclusions:Conservative therapy of DDH (Graf type IIc, D, III) with the Pavlik harness has demonstrated very good therapeutic success and a very low rate of residual dysplasia (2.81%). Both the radiologic and clinical outcomes were highly satisfactory. LEVEL OF EVIDENCE: Level IV.

Progressive lateralization and constant hip geometry in children with DDH, NDH, and LCPD following hip reconstructive surgery: a cohort study of 73 patients with a mean follow-up of 4.9 years.

BACKGROUND: Pelvic and femoral osteotomies have been effective methods to treat developmental dysplasia of the hip (DDH), neurogenic dislocation of the hip (NDH), and Legg-Calvé-Perthes disease (LCPD). The aim of this study was to evaluate the mid-term results after hip reconstruction in children with DDH, NDH, and LCPD. METHODS: In a retrospective study, X-rays of 73 children (2-19 years) with DDH, NDH, and LCPD were measured before, 3 months, and at final follow-up (FU) after hip reconstructive surgery (open reduction, and femoral and/or pelvic osteotomy ± soft-tissue procedures between 2008 and 2018). Measurement of hip geometry included acetabular index (AI), center-edge angle (CE), and Reimers migration index (RMI). Mean follow-up time at final FU was 4.9 years. P value was set P < 0.05. RESULTS: After surgery (femoral osteotomy: 84 hips, Salter innominate osteotomy: 21 hips, Pemberton osteotomy: 30 hips, open reduction: 28 hips, Chiari osteotomy: 4 hips, and soft-tissue release: 24 hips), hip geometry parameters improved significantly. Nevertheless, at final FU, there was deterioration in hip geometry with femoral head lateralization (RMI) compared to the data at 3 months after surgery (RMI: preop/3 months/final FU: 40.6 ± 16.1%/6.1 ± 9.0/15.4 ± 16.0%; CE: 11.3° ± 20.0°/30.2° ± 9.5°/27.9 ± 15.4°; AI: 28.8° ± 9.6°/19.1° ± 7.6°/18.3 ± 7.6°). Sub-group analysis did not show differences concerning the progression of RMI in DDH, NDH, and LCPD at final FU. Regardless of basic disease, the lateralization was observed in all three groups (DDH, NDH, and LCPD) and statistically significant comparing X-rays 3 months postoperatively to maximum follow-up (DDH; NDH; LCPD: 2.7 ± 6.8%/7.6 ± 10.1%; 13.7 ± 15.3%/22.8 ± 19.8%; 1.7 ± 4.1%/14.9 ± 11.3%). Additional soft-tissue release techniques in patients with DDH or NDH did not show postoperative differences with statistical significance. Concerning surgical techniques, a connection between the lower RMI and the procedure of osteotomy of the ilium was found. In 25 patients, (34%) complications were observed: superficial skin lesions in 8, deep skin lesions in 3, contraction of adductors in 3, subluxation in 2, dislocations of the cast in 2, osteonecrosis of the femoral head in 2 cases, reluxation in 1, infection of the implanted plate in 1, compliance problem in 1, delayed bone healing in 1, and contraction of knee flexors in 1 case. DISCUSSION: The basic results of this study show a significant improvement of hip geometry at a follow-up of 4.9 years and prove findings of previously published literature. Moreover, the study was able to show a progression of RMI in all patient groups, which have undergone reconstructive surgery, despite basic hip geometry data (AI, CE angle) did not change. Those findings were independent from underlying pathology. Complications were counted in 34% of the patients and involved all known adverse events after hip reconstructive surgery. This makes clear why annual follow-up checks are needed not to miss the right indication for revision surgery. CLINICAL RELEVANCE: Evidence level: Level IV, case series. TRIAL REGISTRATION: This manuscript is part of a prospective randomized clinical trial, registered in the German Clinical Trials Register DRKS-ID: DRKS00016861.

Tendon transfer in foot drop: a systematic review.

INTRODUCTION: Foot drop is a disorder that impairs walking and leads to tripping and falling. Tendon transfer (e.g., tibialis posterior tendon) is a typical secondary procedure in foot drop treatment. The purpose of this systematic review was to identify the most common tendon transfer techniques for treating foot drop and to analyze the reported functional outcomes. Furthermore, it was of interest if the type of surgical technique affects the functional outcome. METHODS: A PubMed and MEDLINE literature search was performed according to PRISMA guidelines. The search terms used were ("tendon transfer" OR "tendon transposition") AND ("foot drop" OR "peroneal neuropathies"). Any study published before January 2020 was considered for inclusion. No case reports or reviews were included. Common outcome measures (Stanmore score, AOFAS, FAAM, AFO use, patient satisfaction and active ankle dorsiflexion) were evaluated. The quality of the included studies was assessed using the Coleman Methodology Score. RESULTS: Of the 125 reviewed publications, 37 met the inclusion criteria. 42 cohorts were analyzed. The frequently reported tendon transfer technique was the tibialis posterior tendon transfer through the interosseus membrane. The most used fixation technique was tendon on tendon fixation; however in recent years, a tendon to bone fixation has gained popularity. There was an increase in Stanmore scores and AOFAS postoperatively and a decrease of AFO use postoperatively observed. CONCLUSIONS: Due to various outcome measures and lack of preoperative assessment in the included studies, a meta-analysis of the pooled results was not possible. Nevertheless, the findings of this study show that tendon transfer increases mobility and self-independency leading to patient satisfaction. The choice of the surgical technique does not affect the outcome. A prospective collection of patient data and standardized outcome measures will be important to further analyze the efficacy of tendon transfer techniques.

Mid-Term Results of Distal Femoral Extension and Shortening Osteotomy in Treating Flexed Knee Gait in Children with Cerebral Palsy.

Background: Distal femoral extension and shortening osteotomy (DFESO) seems to be an effective method for the treatment of flexed knee gait in children with cerebral palsy. Nevertheless, studies investigating the mid- and long-term outcomes after such procedures are lacking in the literature. Therefore, the purpose of this study was to assess the mid-term outcomes regarding sagittal plane kinematics of the knee after DFESO with or without concomitant patella advancement. Furthermore, an evaluation of the postoperative course and possible recurrence of flexed knee gait was planned. Methods: In a prospective observational study, 19 patients (28 limbs; mean age 11.8 years (6.7-16.0 years)) were examined using 3-D gait analysis and clinical exam before (E0) and at a mean of 38 months (E2: 24-55 months) after surgery. Fifteen patients (22 limbs) had an additional first postoperative gait analysis (E1) after a mean of 14 (10-20) months after surgery. In these patients, the postoperative changes between the short-term and mid-term gait analyses were evaluated. Results: DFESO led to a significant decrease in flexed knee gait with an improvement in sagittal plane kinematics during the stance phase. In addition, a slightly increased anterior pelvic tilt was observed at E1, and we found a tendency towards stiff knee gait with a decrease in mean knee flexion in swing at E2. Conclusions: DFESO led to a significant improvement in flexed knee gait in children with cerebral palsy. The therapeutic effect seems to be lasting on mid-term follow-up with a slight overall tendency to recurrence.

High Reoperation Rate in Mobile-Bearing Total Ankle Arthroplasty in Young Patients.

Background and Objectives: Due to inferior survival rates compared to hip and knee arthroplasty, total ankle arthroplasty (TAA) was previously mainly recommended for older and less active patients. However, given the encouraging survival rates and clinical outcomes of modern generations of TAA, some authors have also advocated TAA in young patients. Thus, the aim of this study was to evaluate age related reoperation, revision and survival rates of third-generation mobile-bearing TAAs. Materials andMethods: In this retrospective study, 224 consecutive TAA patients with a minimum follow up (FU) of 2 years were analyzed. Patients were retrospectively assigned to two study groups (Group A: age < 50 years; Group B: age ≥ 50 years). Revision was defined as secondary surgery with prothesis component removal, while reoperation was defined as a non-revisional secondary surgery involving the ankle. Results: After a mean FU of 7.1 ± 3.2 years, the reoperation rate (Group A: 22.2%; Group B: 5.3%; p = 0.003) and revision rate (Group A: 36.1%; Group B: 13.8%; p = 0.003) were higher within Group A. An age of under 50 years at time of surgery was associated with higher reoperation (odds ratio (OR): 6.54 (95% CI: 1.96-21.8); p = 0.002) and revision rates (OR: 3.13 (95% CI: 1.22-8.04); p = 0.018). Overall, lower patient age was associated with higher reoperation (p = 0.009) and revision rates (p = 0.001). Conclusions: The ideal indication for TAA remains controversial, especially regarding patient age. The findings of this study show high reoperation and revision rates in patients aged under 50 years at time of surgery. Therefore, the outcomes of this study suggest that the indication for TAA in young patients should be considered very carefully and that the association between low patient age and high reoperation rate should be disclosed to all eligible patients.

A single-surgeon experience in reconstruction of femoro-acetabular offset and implant positioning in direct anterior approach and anterolateral MIS approach with a curved short stem.

PURPOSE: Minimally invasive surgery using short stems in total hip arthroplasty gained more popularity. The differences in change of hip offset and implant positioning in minimally invasive approaches are not fully known. Therefore, this study was conducted to evaluate the difference in reconstruction of hip offset and implant positioning in direct anterior approach (DAA) and minimally invasive anterolateral approach (AL MIS). METHODS: A single surgeon series of 117 hips (117 patients; mean age 65.54 years ± 11.47; index surgery 2014-2018) were included and allocated into two groups: group A (DAA) with 70 hips and Group B (AL MIS) with 47 patients operated. In both groups the same type of cementless curved short hip stem and press fit cup was used. RESULTS: Both groups showed an equal statistically significant increase of femoral (p < 0.001) and decrease of acetabular offset (p < 0.001). Between both groups no statistically significant difference in offset reconstruction, leg length difference or implant positioning could be found. Leg length increased in both groups significantly and leg length discrepancy showed no difference (group A: - 0.06 mm; group B: 1.11 mm; p < 0.001). A comparable number of cups were positioned outside the target zone regarding cup anteversion. CONCLUSION: The usage of a curved short stem shows an equal reconstruction of femoro-acetabular offset, leg length and implant positioning in both MIS approaches. The results of this study show comparable results to the existing literature regarding change of offset and restoration of leg length. Malposition of the acetabular component regarding anteversion poses a risk.

Digital templating for the implantation of a curved short hip stem with an anterolateral MIS approach shows gender differences in digital templating.

PURPOSE: Digital templating shows reliable accuracy for straight stem systems. In recent years, the implantation of short stems through minimally invasive approaches has gained more popularity. Minimally invasive approaches (MIS) show the risk of undersizing femoral components. Therefore, we questioned the planning adherence for a curved short stem and a bi-hemispherical acetabular cup implanted through an anterolateral MIS approach. METHODS: A consecutive series of 964 hips (index surgery between 2014 and 2019) with Fitmore® curved short stem and Allofit/-S® acetabular cup (both ZimmerBiomet Inc, Warsaw, IN) were included. Preoperative digital templating was conducted anterior-posterior (AP) digital radiographs of the hip using mediCAD® version 5.1 (Hectec GmbH, Altdorf, Germany). The templates of acetabular and femoral components (offset option and stem size) were retrospectively evaluated for general adherence, and according to sex, BMI and planner's experience. RESULTS: Planning adherence for the exact offset option was 70.6 and 21.6% for exact offset option and stem size. Adherence for acetabular cup ± 1 size was 74.8%. A significant difference between male and female patients for the offset option could be found (p = 0.03, z = -2983). In 22.5% of male patients, an offset option one size higher and in 12.3% of female patients an offset option one size smaller than templated was used intraoperatively CONCLUSION: Digital templating for the Fitmore® stem in cementless THA with a minimally invasive anterolateral approach shows comparable planning adherence to the existing literature for this cementless short stem. However, a lower planning adherence was detected compared to conventional straight stem systems. In male patients, the femoral offset is frequently undersized and in female patients frequently oversized compared to the preoperative plan. Surgeons should be aware of this difficulty in digital templating for Fitmore® hip stem.

Bioabsorbable implants in forefoot surgery: a review of materials, possibilities and disadvantages.

Bioabsorbable and biodegradable implants offer new possibilities in orthopaedic and trauma surgery. As soon as the initial stability of the degradable implants has reached the qualities of conventional materials, new devices may find usage in younger and more demanding patients. Residual conventional osteosynthetic material or the necessity to remove metal increasingly seems to be more of an adverse event than daily practice in forefoot surgery. Nevertheless, some drawbacks need to be discussed. Recent literature screened for the use of bioabsorbable and biodegradable materials in forefoot surgery, available implants and indications in forefoot surgery were analysed and summarized. Apart from common indications in forefoot surgery, points of interest were the type of biomaterial, the process of biodegradation and biointegration, and possible adverse events. Materials were comprehensively discussed for each indication based on the available literature. Polylactide, polyglycoside and polydioxanone are considered safe and sufficiently stable for use in forefoot surgery. Low complication rates (e.g. 0.7% for pin fixation in hallux deformities) are given. Magnesium implants suffered from an extensive corrosive process in the first generation but now seem to be safe in forefoot surgery and offer good options compared with conventional titanium screws, especially in procedures of the first ray. Allograft bone has proven feasibility in small case series, but still lacks larger or randomized clinical trials. The first results are promising. Bioresorbable and osseointegrating devices offer attractive new possibilities for surgeons and patients. Despite all the known advantages, the difficulties and possible complications must not be forgotten, such as soft tissue reactions, unwanted osteolysis and a lower primary mechanical load capacity.

Long-Term Results of a Second-Generation, Small-Diameter, Metal-On-Metal Bearing in Primary Total Hip Arthroplasty at 14-year Follow-Up.

(1) Background: The objective of the present study was to review the clinical and radiological results of a small-head, MoM bearing in primary THA and to determine blood metal ion levels at long-term follow-up. (2) Methods: We retrospectively evaluated the clinical and radiological results of 284 small-diameter, MoM 28-mm Metasul THA at a mean follow-up of 14.5 years, and measured blood metal ion concentrations in 174 of these patients. (3) Results: After 14 years, survival free for revision due to any reason was 94%. Proximal femoral osteolysis was seen in 23% of hips, and MRI demonstrated ARMD in 27 of the 66 investigated hips (41%). Mean cobalt, chromium, and titanium ion concentrations were 0.82 µg/L (range 0.22-4.45), 1.51 µg/L (0.04-22.69), and 2.68 µg/L (0.26-19.56) in patients with unilateral THA, and 2.59 µg/L (0.43-24.75), 2.50 µg/L (0.26-16.75), and 3.76 µg/L (0.67-19.77), respectively in patients with bilateral THA. Twenty-nine percent of patients showed cobalt or chromium ion levels > 2 µg/L. (4) Conclusions: Despite good clinical long-term results, increased blood metal ion levels (cobalt or chromium > 2 µg/L) were found in approximately one-third of asymptomatic patients, and proximal femoral osteolysis and ARMD were frequently seen in this cohort. Blood metal ion analysis appears helpful in the long-term follow-up of these patients in order to identify individuals at risk. In accordance with contemporary consensus statements, symptomatic patients with elevated metal ion levels and/or progressive osteolysis should be considered for additional CT or MARS MRI to determine the extent of soft tissue affection prior to revision surgery. Further studies are necessary to investigate the clinical relevance of ARMD in asymptomatic patients with small-head, MoM THA.

Long-term muscle changes after hamstring lengthening in children with bilateral cerebral palsy.

AIM: To evaluate short-term (1y postoperatively; E1) and long-term (at least 4y postoperatively; E2) changes in hamstring muscle-tendon length (MTL) and lengthening velocity after hamstring lengthening in children with bilateral cerebral palsy (CP). METHOD: Three-dimensional gait analysis was performed in 19 children (16 males, 3 females; 36 limbs; mean age at surgery 9y [SD 3y]; range 6-10y) with flexed knee gait, preoperative ankle dorsiflexion lower than 20 degrees, and CP before bilateral hamstring lengthening (E0), at E1 and E2. Hamstring MTL (normalized by leg length) and velocity were assessed via OpenSim software. RESULTS: MTL increased from E0 to E1 (p=0.004) and decreased from E1 to E2 (p<0.020). Hamstring lengthening velocity did not change. In the subgroup with short, not slow hamstrings, the increase in MTL was maintained at E2. INTERPRETATION: Hamstring lengthening is an efficient procedure to lengthen short and/or slow hamstrings short-term. The desired outcome with maintenance of the postoperative changes in hamstring MTL is only achieved for preoperatively short, not slow hamstrings. WHAT THIS PAPER ADDS: Surgical hamstring lengthening can be confirmed via musculoskeletal modelling in OpenSim software. Surgical hamstring lengthening in cerebral palsy does not change hamstring lengthening velocity. Short, not slow hamstrings present a long-lasting muscle-tendon length (MTL) increase after hamstring lengthening. Changes in MTL after hamstring lengthening cannot be maintained for slow hamstrings. MTL does not change after hamstring lengthening for neither short nor slow hamstrings.

CAMBIOS MUSCULARES A LARGO PLAZO DESPUÉS DEL ALARGAMIENTO DE LOS ISQUIOTIBIALES EN NIÑOS CON PARÁLISIS CEREBRAL BILATERAL: OBJETIVO: Evaluar los cambios a corto plazo (un año después de la operación; E1) y a largo plazo (al menos cuatro años después de la operación; E2) de la longitud del tendón muscular de los isquiotibiales (LT) y la velocidad de alargamiento después del estiramiento en niños con parálisis cerebral bilateral (PC). MÉTODO: Se realizó un análisis tridimensional de la marcha en 19 niños (16 varones, tres mujeres; 36 extremidades; edad media en la cirugía 9 años [DS 3 años]; rango 6-10 años) con la marcha en flexión de la rodilla, dorsiflexión preoperatoria del tobillo inferior a 20 grados, antes del alargamiento bilateral de los isquiotibiales (E0), en E1 y E2. El LT de los músculos isquiotibiales (normalizado por la longitud de la pierna) y la velocidad fueron evaluadas mediante el OpenSim. RESULTADOS: El LT aumentó de E0 a E1 (p = 0,004) y disminuyó de E1 a E2 (p<0,020). La velocidad de alargamiento de los isquiotibiales no cambió. En el subgrupo con isquiotibiales cortos, pero no lentos, el aumento de la LT se mantuvo en E2. INTERPRETACIÓN: El alargamiento de los isquiotibiales es un procedimiento eficiente para los isquiotibiales cortos y/o lentos a corto plazo. El resultado deseado con el mantenimiento de los cambios postoperatorios en la longitud de los isquiotibiales solo se logra para los isquiotibiales cortos no lentos antes de la operación.

ALTERAÇÕES MUSCULARES A LONGO PRAZO APÓS ALONGAMENTO DE ISQUIOTIBIAIS EM CRIANÇAS COM PARALISIA CEREBRAL BILATERAL: OBJETIVO: Avaliar a curto (um ano de pós-operatório; E1) e longo prazo (no mínimo quatro anos de pós-operatório; E2) alterações no comprimento do tendão do músculo (CTM) isquiotibial e a velocidade de estiramento após alongamento do isquiotibial em crianças com paralisia cerebral bilateral (PC). MÉTODO: Foi realizada a análise tridimensional da marcha em 19 crianças (16 meninos, três meninas; 36 membros; média de idade de cirurgia de 9 anos [DP 3 anos]; variação de 6-10 anos) com marcha com flexão de joelho, ângulo de dorsiflexão de tornozelo menor que 20o no pré-operatório, e PC antes do alongamento bilateral dos isquiotibiais (E0), em E1 e E2. CTM dos isquiotibiais (normalizado pelo comprimento da perna) e a velocidade foram avaliados pelo OpenSim. RESULTADOS: CTM aumentou de E0 para E1 (p=0,004) e diminuiu de E1 para E2 (p<0,020). A velocidade de estiramento do isquiotibial não mudou. No subgrupo com isquiotibial encurtado e não lento, o aumento no CTM foi mantido em E2. INTERPRETAÇÃO: O alongamento do músculo isquiotibial é um procedimento eficiente para alongar isquitotibiais encurtados e/ou lentos a curto prazo. O resultado desejado com a manutenção das alterações no pós-operatório no CTM do isquiotibial é atingida somente para isquiotibial curto e não lento no pré-operatório.

Supracondylar femoral rotation osteotomy affects frontal hip kinetics in children with bilateral cerebral palsy.

AIM: To evaluate the influence of supracondylar femoral derotation osteotomy (FDO) on hip abduction muscle force and frontal hip moments in children with bilateral cerebral palsy. METHOD: For this retrospective cohort study 79 children (36 females, 43 males; mean age at surgery 11y [SD 3y]; range 4-17y) with bilateral cerebral palsy and preoperatively and 1-year postoperatively documented frontal hip moments who received supracondylar FDO in 134 limbs were included. The control group consisted of eight children (two females, six males; mean age 11y [SD 4y]; range 5-17y) who received single-event multi-level surgery without FDO. RESULTS: Hip joint impulse (p<0.001) and the first peak of frontal hip moments (p=0.003) increased, whereas the second peak decreased (p<0.001) from preoperatively to postoperatively. Hip abductor strength improved (p=0.001) from preoperatively to postoperatively. INTERPRETATION: Despite the compensatory mechanism, frontal hip moments are decreased preoperatively. Supracondylar FDO results in increased frontal hip moments. Changes in anteversion directly influence hip kinetics, although no direct change of the proximal bony geometry is performed. WHAT THIS PAPER ADDS: Internal rotation gait cannot fully restore the frontal hip moment. Supracondylar femoral derotation osteotomy (FDO) influences frontal hip kinetics in children with bilateral cerebral palsy. Supracondylar FDO changes the curve progression of frontal hip moments. Supracondylar FDO restores the hip abductor moment arm. Supracondylar FDO leads to an increase in hip abductor muscle force.

Can intraoperative measurement of bone quality help in decision making for cementless unicompartmental knee arthroplasty?

BACKGROUND: In uncemented total hip arthroplasty (THA), low bone mineral density (BMD) is associated with aseptic loosening. BMD is usually assessed via dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography, which takes time and exposes patients to radiation. Due to its low risk profile, intraoperative measurement of the trabecular stability might be a useful alternative to DXA. METHODS: In 24 human femora, BMD was analysed using DXA at the femoral necks and the knees. Performing the standard Oxford Unicompartmental Knee Arthroplasty (OUKA) implantation procedure, a wingblade (DensiProbe) coupled to a torque probe was used to evaluate the trabecular peak torque. The standard procedure was modified: before the completion of the central peg drill hole, the DensiProbe was inserted into the pre-drilled hole and then turned until a loss of resistance was achieved. The obtained data was then correlated with BMD at the femoral neck as well as the knee. RESULTS: In all tested regions, a higher peak torque was observed in correlation with a higher BMD. CONCLUSIONS: As demonstrated, the DensiProbe can be a helpful tool to assess the bone quality intraoperatively in OUKA. It can be a valuable decision guidance when faced with choosing between a cemented and a cementless implant. Due to the fact that the central peg hole of the OUKA can be used for the procedure, no additional risk for the patient exists, while the additional work for the surgeon is minimal.

Equinus Correction During Multilevel Surgery in Adults With Cerebral Palsy.

BACKGROUND: Equinus foot deformity constitutes a common gait disorder in ambulatory adults with bilateral spastic cerebral palsy (BSCP). The outcome after intramuscular aponeurotic lengthening in the context of single-event multilevel surgery (SEMLS) in adulthood has not been investigated. METHODS: We followed a group of 31 ambulatory adults with BSCP and equinus who underwent SEMLS including gastrocnemius-soleus intramuscular aponeurotic recession or Achilles tendon lengthening. All patients were analyzed preoperatively and at least 1 year (mean follow-up period: 1.6 years) postoperatively by clinical examination and 3-dimensional instrumented gait analysis including the Gait Profile Score (GPS). RESULTS: Clinical examination showed no significant improvement of ankle dorsiflexion ( P = .5) and an unchanged plantarflexion ( P = .7) with knee extended but a significant postoperative reduction of spasticity in the calf muscle ( P = .0001) as measured by clinical examination following the modified Ashworth scale. Significant improvement of mean ankle dorsiflexion in stance and swing ( P = .0001) was found. The GPS decreased and improved significantly (15.9 ± 4.6 to 11.4 ± 3.1; P = .0001). Persistence of equinus and calcaneal gait indicating under- and overcorrection at follow-up was found in 1 patient (3%), respectively. CONCLUSION: Intramuscular gastrocnemius-soleus aponeurotic recession is part of multilevel surgery corrected equinus deformity in adults. The increase in muscle length led to significant improvement of kinetic and kinematic parameters during walking without a loss of muscle strength and push-off capacity. The risk of overcorrection after equinus correction in adults with BSCP was found to be relatively low. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Mid-term development of hamstring tendon length and velocity after distal femoral extension osteotomy in children with bilateral cerebral palsy: a retrospective cohort study.

AIM: Flexed knee gait can be treated with distal femoral extension osteotomy (DFEO) and additional patellar tendon advancement (PTA) in children with cerebral palsy (CP). This study assesses changes in hamstring muscle tendon length (MTL) and velocity after DFEO (+PTA). METHOD: Nineteen children (mean age 13y [standard deviation 3y] at surgery) with CP and flexed knee gait who were treated with DFEO (15 limbs) or DFEO+PTA (10 limbs) were retrospectively included in this study. Gait analyses were performed preoperatively (E0), 1 year postoperatively (E1), and for 10 limbs additionally 2 to 5 years postoperatively (E2). Hamstring MTL and velocities were assessed at all examination dates using OpenSim. RESULTS: Hamstring MTL and velocity did not change significantly over time. From E0 to E1, knee flexion in stance improved for both DFEO and DFEO+PTA (p<0.05), knee flexion in swing only improved after DFEO+PTA (p<0.05). The improved knee flexion in stance and swing was maintained at E2. INTERPRETATION: DFEO led to a significant improvement in knee kinematics at E1 which was maintained at E2. DFEO seems to prevent recurrent hamstring tightness but does not lead to lengthened or fastened hamstrings. WHAT THIS PAPER ADDS: Distal femoral extension osteotomy (DFEO) does not change hamstring muscle tendon length. DFEO does not change hamstring lengthening velocity. DFEO leads to a significant improvement in knee kinematics. Changes in knee kinematics after DFEO can be maintained at mid-term. DFEO seems to prevent recurrent hamstring tightness.

Treatment of High-Grade Acetabular Defects: Do Porous Titanium Cups Provide Better Stability Than Traditional Titanium Cups When Combined With an Augment?

BACKGROUND: Revision total hip arthroplasty frequently faces challenges associated with deficient bone stock. Porous metal implants were developed to meet the challenge, but require rapid osseointegration for ultimate success. This study aims to assess relative motion as an indicator for primary stability and osseointegration of two different titanium cups each combined with a titanium augment. METHODS: In 14 cadaver hemipelvises, 2 types of titanium acetabular cups, a traditional sintered-bead cup (POROCOAT Acetabular Cup [PAC]) and a newer porous-coated cup (GRIPTION Acetabular Cup [GAC]) each associated with a porous augment, were subjected to 3-dimensional varying loads, replicating 30% of loads experienced during normal gait. Relative motion was measured at the cup/bone, augment/bone, and cup/augment interfaces. RESULTS: Only at the cup/bone interface was there a statistically significant difference in relative motion between the traditional PAC and the newer GAC, with PAC showing less relative motion (P = .0037). Bone mineral density (BMD) had a significant effect on relative motion (P = .0019) at the cup/bone interface of both cup types, with low BMD specimens showing more relative motion. CONCLUSION: Both cup types combined with augments displayed minimal relative motion that was within the accepted range thought to allow osseointegration, although the traditional surface proved superior to the newer surface. This difference was more pronounced at low BMD, with the well-established PAC cup displaying less relative motion than the more porous GAC cup, consistent with better osseointegration than the more porous cup. This suggests that the more porous implant may be less advantageous than traditional PAC cups, particularly in cases with poorer bone stock.

Long-term development of overcorrection after femoral derotation osteotomy in children with cerebral palsy.

BACKGROUND: Recent studies showed rates of recurrence of internal rotation gait (IRG) after femoral derotation osteotomy (FDO) up to 40%. Some surgeons even advice overcorrection during FDO to avoid a later recurrence. RESEARCH QUESTION: Evaluation of the long-term development of limbs with initial overcorrection after FDO. METHODS: 29 limbs of 20 children (9.9 ±â€¯3.2 years at surgery) with IRG, cerebral palsy (CP) and more than 5° external hip rotation postoperatively were included retrospectively. A gait analysis and clinical examination were performed preoperatively (less than one year, E0), postoperatively (9-23 months, E1) and at the long-term follow-up (at least five years postoperatively, E2). Differences between those children that remained overcorrected at E2 and those with a hip rotation within normal range at E2 were evaluated. RESULTS: At E2 41% of these limbs remained overcorrected, 52% showed a hip rotation within normal range and 7% showed recurrence of IRG. A comparison of those limbs that remained overcorrected and those ending within normal range revealed neither a difference in age at surgery nor in static and dynamic torsional parameters at E0 and E1 except for pelvic rotation. A significantly larger pelvic internal rotation at E1 for those with remaining overcorrection could be identified. SIGNIFICANCE: A general overcorrection during FDO in children with CP to avoid recurrence of IRG cannot be recommended, as 41% remain overcorrected. Preoperative predictors for long-term development couldn't be identified. If pelvic mal-rotation is corrected, hip rotation may change into normal range over the time in combination with the development of a flexed knee gait.

Comparison of the Primary Stability of a Porous Coated Acetabular Revision Cup With a Standard Cup.

BACKGROUND: The number of revision hip arthroplasty procedures has been increasing substantially, with the acetabular component requiring component revision in over half of the cases. New porous implant designs attempt to improve outcomes due to improved osseointegration; however, sufficient primary stability is paramount for good osseointegration. METHODS: We compared 2 revision cups of the same geometry, yet different surface properties in an in vitro scenario: a porous titanium surface and a conventional sintered-bead titanium surface. These were tested in 10 cadaveric pelvises under a physiologic cyclic partial weight-bearing scenario. Each side was randomly implanted with one of the implants. Relative motion between the bone and cup was measured using an optical measuring device. Statistical evaluation was carried out descriptively using a covariance analysis with repeated measures and a test of fixed effects, with significance determined as P < .05. RESULTS: The conventional cup displayed an average relative motion of 28.02 µm; and the porous implant displayed an average relative motion of 33.42 µm. There was no statistically significant difference between the two with regard to the resultant relative motion (P = .2649). The bone mineral density does have a significant influence on resultant relative motion (P = .0406), with higher bone mineral density correlating with less relative motion in both implants. CONCLUSION: The porous implant provides similar primary stability to the conventional implant in the tested scenario; the motion of both implants relative to the bone was within safe limits for osseointegration. Bone stock must be considered when choosing implant type and postoperative care.

MRI Findings in Patients After Small-Head Metal-on-Metal Total Hip Arthroplasty with a Minimum Follow-up of 10 Years.

BACKGROUND: Concern has been raised about the late onset of adverse reactions to metal debris (ARMD) in patients with a small-head metal-on-metal total hip replacement. The aims of this study were to assess the frequency and characteristic appearance of ARMD in patients with a small-head (28-mm) metal-on-metal total hip replacement and elevated blood ion levels (>1 µg/L) after a minimum follow-up of 10 years and to analyze the possible risk factors associated with the prevalence of these lesions. METHODS: In the present study, we used metal artifact reduction sequence magnetic resonance imaging (MARS MRI) to investigate the cases of 53 patients (66 hips) with a small-head (28-mm) metal-on-metal total hip replacement and elevated blood ion levels at a mean follow-up interval of 15.5 years (range, 10.6 to 19.3 years). Whole blood metal ion levels (cobalt and chromium), clinical outcome scores (Harris hip score), and radiographs were obtained for each patient. Tissue samples from patients who had revision surgery were histologically examined. RESULTS: MARS MRI revealed ARMD in 27 hips (41%). Most hips with ARMD (67%) were asymptomatic. ARMD were generally small, with a median lesion size of 2.3 cm (range, 0.3 to 71.4 cm) and predominantly cystic in nature. Multivariate regression analysis revealed positive correlation between cobalt ion levels and the presence of ARMD. In this case series, the risk for the development of ARMD was 2.87 times higher for every 1 µg/L increase of blood cobalt ion concentration (95% confidence interval, 1.01 to 8.17; p = 0.048). CONCLUSIONS: In this case series, ARMD were seen in 41% of the hips following small-head metal-on-metal total hip arthroplasty at long-term follow-up, and most patients with ARMD were asymptomatic. Blood cobalt ion levels could be identified as a risk factor for ARMD. However, ARMD also occurred in patients with low metal ion levels. Further studies are necessary to investigate the role of ARMD in asymptomatic patients with this bearing type. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Cementing a polyethylene cup into a well fixed acetabular metal-on-metal resurfacing component? An experimental investigation.

INTRODUCTION: Adverse reactions to metal debris often indicate revision surgery in metal-on-metal (MoM) hip arthroplasty and an exchange of the MoM bearing into either a metal on polyethylene or a ceramic-on-polyethylene articulation. At the moment the removal of the entire implant system is the most reasonable method. In order to avoid bone loss caused by the removal of a well-fixed acetabular component, the purpose of this study was to measure the stability of a cemented polyethylene (PE) cup in an acetabular hip resurfacing component and to examine if such a method could be suitable for clinical use. METHODS: PE cups were cemented into 2 different hip resurfacing components and biomechanical tests were applied to measure failure torques under lever out and rotational load. RESULTS: In all cases failure of the interface between the resurfacing components and the cement layer occurred at a very low load (0.14 Nm-61.50 Nm). DISCUSSION: The early failure occurred due to lacking interdigitation of cement and the polished metal surface. Thus we warn against cementing a PE cup into acetabular hip resurfacing components for clinical use.

Distal femoral extension and shortening osteotomy as a part of multilevel surgery in children with cerebral palsy.

BACKGROUND: There are several reports describing an increase in anterior pelvic tilt after hamstring lengthening in children with cerebral palsy (CP). Distal femoral extension and shortening osteotomy (DFESO) is an alternative treatment for correction of flexed knee gait, but investigations analyzing outcome and influence on adjacent joint are few in the literature. The purpose of this study was to analyze the influence of DFESO on knee and pelvis in children with CP. Furthermore, it was of interest if an additional patellar tendon advancement (PA) influences outcome. METHODS: In this retrospective study, 31 limbs of 22 children (GMFCS I-III; mean age: 12.1±3.1 years), who received DFESO were included and kinematic parameters (knee, pelvis) measured by 3-D-gait analysis were compared before and at least 1 year after surgery (mean follow-up period: 15.6 months). RESULTS: After surgery, during stance phase minimum knee flexion improved significantly by 20.5° (P<0.001) and mean anterior pelvic tilt increased by 4.0 degrees (P=0.045). In 16 limbs, the postoperative increase in maximum anterior pelvic tilt was more than 5°. Limbs who received an additional PA showed the biggest increase in anterior pelvic tilt. CONCLUSIONS: DFESO is an effective method for correction of flexed knee gait in children with CP. Furthermore, the results of this study indicate that DFESO may lead to an increase in anterior pelvic tilt, which may lead to a recurrence of flexed knee gait. In this context, PA seemed to aggravate the effect on the pelvis.